The Yellow Sea experienced glacio-eustasy sea-level fluctuations during the Quaternary period. In the middle part of the Yellow Sea, the Quaternary successions were accumulated by alternating terrestrial, paralic, and shallow marine deposits that reflected the fluctuating sea levels. A long core of 69.2 m was acquired at the YMGR-102 site (33o50.1782'N and 123o48.3019'E) at a depth of 72.5 m in the middle of the Yellow Sea. A four-layered geoacoustic model was reconstructed for the sedimentary succession. It was based on seismic characteristics from 3.5 kHz SBP and air-gun seismic profiles and 96 grain-size properties in the core sample from YMGR-102. For the underwater simulation and experiments, the in-situ P-wave speeds were calculated using the sound speed ratio of the Hamilton method. The geoacoustic model of YMGR-102 can contribute to the reconstruction of geoacoustic models, reflecting the vertical and lateral variability of the acoustic properties in the continental shelf of the middle Yellow Sea.
To investigate seasonal variation of fisheries resources composition and their correlationships with environmental factors in the coastal ecosystem of the middle Yellow Sea of Korea, shrimp beam trawl were carried out for the fisheries survey. Fisheries resources of 81 species, 57 families, and 6 taxa totally were collected by shrimp beam trawl in the middle coastal ecosystem of Yellow Sea of Korea. Species were included 6 species in Bivalvia, 6 in Cephalopoda, 22 in Crustacea, 2 in Echinodermata, 5 in Gastropoda, and 40 in Pisces. Diversity indices (Shannon index, H') showed seasonal variation with low value of 2.14 in winter, and high value of 2.67 in spring. Main dominant species were Oratosquilla oratoria, Octopus ocellatus, Acanthogobius lactipes, Cynoglossus joyneri, Rapana venosa venosa, Loligo beka, Chaeturichthys stigmatias, Raja kenojei, Microstomus achne and Paralichthys olivaceus, that were occupied over 58% of total individuals, and 55% of wet weight. Fisheries organism made four coordinative seasonal groups by the principal component analysis (PCA), showing stronger seasonal variation than spatial variation. PC from PCA showed statistically significant cross-correlationships with seawater temperature, NH4-N, TP and chlorophyll a (P 〈 0.05).
상층과 하층의 대기구조 특성을 알아내기 위하여, 해양의 특성을 잘 표현한다고 사료되는 섬(충남 보령시 오천면 외연도리)을 관측지점으로 선택하여 라디오존데를 이용하여 대기의 연직구조를 관측하였다. 관측결과를 이용하여, 저 고기압이 통과할 때의 상대습도, 기온과 바람의 변화를 분석하였으며 각각의 경우에 대해 결과치들을 비교하였다. 해양과 육상에서의 대기구조를 비교하기 위하여 오산의 관측 결과를 분석하였다. 그 결과, 상대습도가 고 저기압의 통과에 따라 변화함을 알 수 있었다. 즉, 저기압이 다가올 때는 상대습도는 하층보다 상층에서 먼저 증가하였으나 고기압이 다가올 때는 상층에서 10%까지 급격하게 감소하였다. 또, 상대습도 변화폭이 육상에서보다 큰 것으로 분석되었다. 앞으로 해양과 육상에서의 수증기간의 관계를 계절별, 그리고 일별로 동시간 관측을 통해 찾고자 한다.